Electric circuits for lamp regulation



Nov. 17, 1942. w. c. HALL, JR 2,302,213

' ELECTRIC CIRCUITS FOR LAMP REGULATION Filed Aug. 7, 1959 3Sheets-Sheet l Inn/ENTER Z NILLHRD E-HHLL,tTR-

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NOV. 17, 194-2. w c; HALL, JR 2,302,213

ELECTRIC CIRCUITS FOR LAMP REGULATION FiledAug. 7, 1959 sshe ets-sn ev'zWILLHRQ EHHLL JR.

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Nov. 17, 1942.

w. c. HALL, JR 2,302,213

ELECTRIC CIRCUITS FOR LAMP REGULATION Filed Aug. '7, 1939 '3Sheets-Sheet 3 INVENTUR WILLHRD E.HHLL,1IR-

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, shoclrs encountered in ordinary use.

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ELECTREG ill 3 s roa Willard 0. Hall, .ln, Los

1- --eles, Califl, assignor 2 Claims.

This invention relates to means and methods for regulating andcontrolling electrical devices and the power factor of the circuitconnected thereto. Although the invention has many uses and adaptationswhen connected with diflerent kinds and types of electrical equipmentsuch as motors, platirg baths, instruments, rectifiers, converters,etc., its principal demand and ad-. vantages is in the regulation andcontrol of lighting devices, particularly for luminous electricdischarge tubes which utilize various gases for conduction of electricalenergy through the tubes.

Such tubes are commonly known as neon tubes even though the rare neongas, which provides the familiar red light, is not present in the tube.Other gases such as argon, helium, carbon dioxide, sodium vapor, mercuryvapor, etc. and mixtures thereof are also used to pro-= vide other lightcolors and various shades thereof. There are many kinds and types of lowand high pressure vapor tubes which consist of various kinds of glass,colored and clear, to withstand the heat evolved and also mechanicalSome of them are coated with a luminescent material to give the efiectdesired. This invention, however, is not limited to any specific type ofilluminating unit or units, but can be altered and arranged to beeffective to improve the operation of any such unit or units whetherconnected in single units or banks of parallel or/ and series units.

The gas pressure in the tube is of importance since this determines thestriking potential and operating voltages to be supplied thereto. Theelectrical characteristics of the electrodes also have some bearing inthe matter, but since they can be accurately predetermined and perfectlydesigned for any particular lamp, they will not be further considered.The major features for consideration in heated cathode tubes are the gaspressure (or pressures where mixtures of gases ductive reactance at thetime the tube is under the influence of the striking voltage, but whenthe tube is at normal operation, the voltage drops from its relativelyhigh value with a proportionate drop across the condenser with theresult that the current lags the voltage but not suriicient to lower thepower factor to less than 90%. Such a circuit is iavored by the powersupply companies over present vapor tube cir-- cuits. Heretofore, so faras known, no means have been provided to automatically improve the powerfactor of vapor tube circuits in asafe and simple manner. Such tubesnormally operate at a 50%, or less, power factor.

The vapor tube circuit embraced by this invention uses no switchingmechanism nor thermostatic devices to accomplish the desired power areemployed) and the fact that when the starting voltage drops the currentincreases. In view of the fact that a relatively high striking voltagemust be initially provided, automatic means must be provided to reducethe striking voltage to a minimum operating value in order to maintainthe current in the circuit at a reasonable value.

This invention keeps the current constant, provides a leading current atthe striking voltage and a power factor of 90% or better during thenormal operation of the vapor tube. This is accomplished by connectingin the circuit a condenser having a reactance greater than the infactorresults or the improved eficiency of vapor tube circuits. The life ofthe tubes, operated in accordance with this invention, are materiallyin= creased because the cathodes thereof are kept at a high emcient heatat all times; this avoids sputtering at the cathodes, and loss ofeficiency because of distortion of the desirable sinusoidal voltage andcurrent wave forms. Therefore, the

current in the tube is kept constant, the illumination always at itsmaximum, and hence its effectiveness 100% from an attractive aspect. Inthe cold electrode type of tube, conditions of operation, as regardsvoltage and current, are quite diderent. In this type of tube, currentpasses by virtue of ionisation by collision of the gas atoms andproduces either a negative or positive glow depending upon the gaspressure and the disposition of the electrodes thereof.

This invention, however, is equally applicable to the so-called coldelectrode lamps as set forth, merely as an example, in one specific formof applying the invention. Since there are a great variety ofilluminating lamps, no attempt is made to apply the invention to everykind of lamp or. other electrical device.

An object of the invention is to provide means and methods for startingand continuously operating electrical devices at a high power factor,and a dependably constant current. Another object is to present anelectrical circuit without mechanical moving parts capable of startingand continuously operating luminous vapor tubes at a power factor of orbetter.

Still another object is to provide means for operating one or more unitsof high or low pres invention will appear from the accompanyingdrawings, the subjoined detailed description, the preamble of thesespecifications and the appended claims.

Applicant is about to illustrate and describe various forms of hisinvention in order to teach one how to make, use and vend the same, but

it is to be understood that the drawings and description thereof are notto limit the invention in any sense whatsoever, except as limited by theappended claims.

In the drawings:

Fig. 1 shows one form of the invention in plan view.

Fig. 2 shows the same inventive form diagrammatically.

Fig. 3 shows a detailed portion of an electric discharge tube.

Fig. 4 shows a slightly modified form of the invention diagrammatically.

Fig. 5 illustrates diagrammatically another form of the invention.

Fig. 6 is a plan view illustrating the manner in which the coils shownin Fig. 5 are preferably mounted upon the same magnetic core.

Figs. 7 and 8 are another form of the invention shown in plan view anddiagrammatically respectively.

In "the preferred form of the invention, as shown in Figs. 1, 2 and 3,the numeral represents an elongated vapor tube having the heatedelectrodes 2 and 3 at the ends thereof. This tube may be of glasscontaining a mixture of argon gas and mercury vapor at a relatively lowvapor pressure. Since the construction and operation of these tubes arewell known, no special details thereof will be given.

The numeral 4 represents a laminated core in the form of a rectanglehaving a closed metallic pathfor the flux thereof. The core has alaminated midway bridge 5 which has its ends slightly spaced from thecore by fiber spacers 6 and 1 which are wedged between the ends of thebridge and the inner sides of the .core as shown.

Mounted upon the core to one side of the bridge is the single coil 8 anda transformer coil 3, the primary being indicated by the referencecharacter l0, and the secondary by the reference character Mounted uponthe core on the opposite side of the bridge 5 is a single coil l2, andthe auto-transformer coil [3.

From the auto-transformer coil l3, at the proper voltage tap, lead thewires M and I5 which are connected to the opposite ends of the heatingelement 3 of the tube. ondary coil ll, lead the wires I6 and II, thewire l6 connecting with one side of the heating element 2 and the wireI! connecting with the other side of said heating element, the wire I?also acting as one of the supply mains and is extended by the wire l8for connection with the city mains of 120 volt, 60 cycle alternatingcurrent. Another supply main l9 leads to the primary winding I0, bestshown in Fig. 2, from the opposite end of which leads a wire connectingwith one end of the coil 8. From the opposite end of the winding of coil8 leads a wire 2| making connection with one end of the coil I2, theother end of this coil winding is connected to a wire 22 which makesconnection with one end of the auto-transformer coil I3. A wire 23,connected to the wire 2|, leads to a set of plates in the condenser 24.From the opposite set of the condenser plates leads a wire 25 whichmakes connection with the wire l6 as shown.

From the sec- The coil sets on either side of the bridge 5 of the corehave equal inductances and are wound giving 120 volts at 60 cycles, thecoils upon the iron core 4 are-preferably arranged as shown in Fig. 1.The coil sets on either side of the bridge 5 is wound with #25 B. & S.gauge copper wire, the combined number of turns for each set being about1980. Since the cathodes 2 and 3 are designed to operate at a potentialof 6.2 volts, a-tap at about 80 turns is made on the auto-transformer |3for heating the element 3 and a secondary winding of 80 turns isutilized in the coil II for th heating of the element 2. At thesevalues, the condenser 24 should have a capacity of about 3 microfarads.Under these conditions, the tube will have a starting voltage of about220 and an operating voltage of 65. At starting, the drop across thecondenser should be- 230 volts and under normal operation of the tubeabout 90 volts. This drop across the condenser shifts the power factorfrom a leading value to about 90% or better at a. lagging position. Thecurrent remains constant at 0.3 ampere under starting and operatingconditions. reading at operating potential is close to 92% where as thestarting potential definitely gives a leading power factor reading.

In the form of the invention shown in Fig. 4, the vapor tube isindicated by the numeral 26 which has the usual heated electrodes at itsends; from one of which leads the wires 21, 28 and from the other wires29 and 30. The induction coil pairs are indicated by 3| and 32, one endof the coil 32 acting as an auto-transformer to feed one of theelectrodes as indicated by the connection of wires 29 and 30, and theother induction 'coil 3| has its end connected to the supply main 33.One end of the coil 3| is shown as having a secondary winding 34 whichsupplies current by the way of Wires 2'! and 28 to the other electrodeof the tube.

The supply main 35 is connected to the electrode feeder wire 28 asshown. As explained in the preferred form of the invention, theinduction coils 3| and 32 are wound oppositely upon the core to causeopposing flux at the ends of the bridge so that it functions as aregulator. In the jointure of the coils 3| and 32 leads a wire 36 whichconnects to one end of a choke coil 31. From the other end of the chokecoil leads a wire 38 connecting with the condenser 39, the other side ofthe condenser having a wire 30 connecting with the electrode feeder wire21.

The only change in this circuit over the one shown in Fig. 2 is theaddition of the choke coil 31 in the condenser line and also thecondenser 39' across the main feeders. This coil functions to avoidserious kickback voltages from the condenser and hence possibleresulting fluctuations in the illumination of the tube.

The circuit including the condenser 39, choke coil 31 and inductancecoil 3| is designed for a resonance balance during the normal operationof the tube 26 while its voltage is at a minimum,

The power factor the power factor at 90% and the frequency 60 cycles.

In the form of the invention shown in Figs. and 6, two vapor tubes areoperated by a common circuit arrangement. The electric discharge tubesare indicated by th'. numerals M and 42. The induction coil bank of thisform of the invention consists of a plurality of coils 43 and 44 whichare wound in opposite directions causing opposing flux in the laminatediron core 45; similar coils 46 and M are mounted on another leg of thecore. A magnetic bridge 48 provides the shunt to avoid fiux flowinterference as set forth in the foregoing forms of the invention.

The end coils 63 and 41 have secondary windings 49 and 50 for feedingthe electrodes 5! and 52 respectively at the ends of tube 42 as shown.The primaries of coils 43 and 41 are tapped at 53 and 54 to provideauto-transformers for feeding the electrodes 55 and 56 respectively ofthe tube 4|. Although the auto-transformer taps are shown as embracingthe same number of turns as the secondaries, this need'not necessarilybe the case since the electrodes of tube 4! may require a higher voltagethan tube 42 because of their lengths or their difierence in design. Thewires connecting the coils with their respective electrodes are shown asthe primes and double primes of their respective electrodes. v Wireconnectors are shown between the various coils, the center connector 51being joined to the supply main 58 of an alternating current source; thefrequency and voltage of which will depend upon the available supply,but since a 60 cycle 120 volt supply is common in this country, such asource is preferred. The other main 59 leads \ia wires 69 and 6| to themiddle tap of the secondary coils 49 and 50 respectively and to aside'of the condenser 62 by a wire 63. The other side of the condenseris joined to a wire 64 which makes connection at the point 65 withtheconnector between the coils 46 and 41.

This form of the invention like the other forms shown in Figs. 1 to 4,has all the same advantages and operating characteristics.

The form of the invention shownin Figs. 7

and 8, appertain to the so-called cold electrode.

type of electrical discharge tube which starts operation by virtue ofatomic bombardment to effect ionisation of the gas. The resulting glowmay be due to either a positive or negative column depending upon thearrangement of the electrodes and the pressure of the confined gas orgases.

In the drawings, the reference character 65 indicates one of theso-called-cold electrode tubes; it being understood, however, that aplurality of such tubes may be connected in series, parallel orseries-parallel arrangement, and the invention would be just aseffective in giving the desired results.

At one end of the tube 65, is an electrode 66 and at the other end,electrode 61. These electrodes are in the form of a coiled wire, theends of which have leads which terminate into a single exterior wire;one such wire is indicated by 68 for the electrode 66 and another wire69 for the electrode 61. Wire 69 is a main as well as the wire llleading to the coil and they are connected to a source of current ofsuitable voltage and frequency.

The coil 10' and its component coil 10" comprise a coil 10 having itswindings arranged to cause flux to flow in the core 12 in the directionOne end of the winding of coil 13' is connected to wire 68 and the otherend to coil 13". Coils 10' and 10 are connected in'series also. The

other ends of the coils 10" and'13" are connected by a wire I5 fromwhich leads a 'wire I6 to one side of the condenser 11. A choke coil 18is inserted between the other side of the condenser and the main 69. Acondenserj'lS is provided across the mains.

In the circuit just described, the tube may contain sodium and mercuryvapors at a pressure of between 8 and 15 mm. of mercury. The voltageacross the mains should be 230 and the frequency 60 cycles. This type ofhigh pressure tube would require a starting line voltage of 230 at 1.8amps, and an operating line voltage of 230 at 3 amps. to maintain thelamp at maximum illumination of about 440 watts input. The lamp runningvoltage itself while cold is 65 which rises almost to line voltage whenat full illumination. The power factor rises as the tube voltageincreases because the drop across the condenser also rises to cause abeneficial increase in capacitive reactance.

During the starting period of the tube, the circuit comprising the coils10', 10" and I8, and

the condenser TI, is near resonance while the this increases theimpedance of the regulator input power is near power factor. As thetemperature of the tube rises, there is a greater voltage drop across itand also across the element l0, l0", l1 and '18, thus increasing theinphase flux in coils l0 and 10" with respect to coils l3 and 13" on thesame magnetic core;

coils. At start, the tube has an input of 200 watts which rises to 440watts at full illumination.

Such tubes in the ordinary circuits take 20 minutes to come to fullillumination from a cold start whereas with this invention applied, thesame tube requires only 15 minutes. Should a break in the current supplyoccur, the tube with the ordinary circuit would require 10 minutes tore-ignite and a few minutes more to come back to full illuminationwhereas when this invention circuit is employed, the tube ignitesimmediately and regains full illumination shortly thereafter. The reasonfor this advantage in applicants circuit appears to be that thecondenser and inductance coils immediately increase the voltage acrossthe tube to substantially twice that of the line voltage. The circuit iskept near resonance at all times, hence a high power factor ismaintained.

At start, on a constant potential line voltage of 220 A. C., a similarlighting tube to the one just explained would draw 0.9 of an ampere or185 watts at a volt-ampere reading of 198, thus working at a powerfactor of 93%. A Five minutes later, the watt meter would read 240- andthe volt-amperes 242 giving a power factor of 95%. Ten minutes later thereading would be 265 watts and 275 va. or 96% P. F.;' fifteen minuteslater 300 w. and 304 va. or 98% P. F.; twenty minutes shown by thearrows. Another composite coil 13 later 320 w. and 330 va. or 97% P. F.In twentyfive minutes, the tube would be at full luminosity and the linereading 400 w. and 418 va., and have a P. F. of 95%. These figures aregiven from an actual test and show that applicant has prerality oflighting devices at a high power factor;-

a magnetic core having long legs joined together by short legs at theends thereof, a magnetic bridge of large cross section wedged betweenthe long legs at the longitudinal centers thereof, a plurality ofinduction coils arranged in series and fixed to the core on the longlegs, said coils being positioned on both sides of the bridge and ar--ranged to cause the fiux generated in the coils of each leg to flow inopposition and then pass across the bridge in a common direction, asupply of electrical current for energizing said coils and devices, acondenser connected between one lead of the electrical supply and apoint between the coils on one leg of the core.

2. An electrical system for starting and main taining gaseous electricdischarge lamps at a high power factor including a magnetic core havingtwo coil legs joined at their ends by means to form an iron circuit, apair of spaced apart coils wound in opposite directions on each coilleg, a. magnetic bridge across the spaces between said coils, said coilshaving a series connection and a wire terminal at each end of the seriesand also at the mid-point of the series, an electric discharge lamphaving a terminal at each end, one terminal of the lamp havingconnection with one end of the series of coils and the other endterminal of the lamp having connection with wire means leading to asource of electrical power, the other end terminal of the coils havingconnection with said power source, and a choke coil and condenserconnected in series and having one end thereof connected to said wiremeans and the other end thereof connected to the mid-point of the coils.

WILLARD C. HALL, JR.

